I’d like to add my own observations (to what others have reported in older threads) that Duplicati on macOS is very slow (compared to Windows). I’ve run it on macOS High Sierra for over a year, and now switched to a new 2018 MacBook Air running Mojave. In both cases, during what I presume is the initial ‘compare’ stage when the backup is starting, it takes easily 30 to 60 minutes before the actual data upload starts, and during this time, the laptop runs hot and the fan goes into overdrive. This results in daily backup times that range anywhere from 45 minutes to 1.5 hours. In comparison, on my Windows 10 laptop, this is done in under ten minutes (total).
I am using client version 184.108.40.206_beta_2018-11-28 (which is the advertised stable build on the Duplicati homepage) with Mono 220.127.116.11. Mojave 10.14.5, 16GB RAM, 512GB storage (half of that used). I am uploading to NextCloud via WebDAV. AES-256, remote volume size is set to 100MB, with backup retention set to delete backups that are older than 12 months.
Any help or suggestions are appreciated.
P.S: Source size is ~190GB, backup size is ~280GB (227 versions)